How Electronic Tattoos Work

Imagine gangs of futuristic bikers as they flex iridescent bicep skulls, or the Tesla coil crackle of tramp stamps on the beach. Surely, humanity's future is bright with the glow of electronic dolphin tattoos and neon back crucifixes.

If that's where your mind is, then here's some hard truth: These are not the electronic tattoos you're looking for. Yet the technology explored in this article is even more amazing -- something that may save untold lives and become a staple of modern medical care. In time, it may change fundamentally what it is to be human.

This thin film of elastic gadgetry is essentially a temporary tattoo -- you know, kind of like those lick-and-peel numbers you used to find in bubblegum wrappers as a kid. Those temporary tattoos were glue-and-ink transfers. Epidermal electronic systems, on the other hand, adhere to skin in a different way. They conform to the skin's texture, sticking firmly in place for a matter of days.

But an electronic tattoo looks less like a fire-breathing dragon and more like a thin circuitry-filled sticker. Also, it doesn't help convince your classmates that you joined a Chinese street gang over the summer. No, instead it reads your vital signs -- eavesdrops on the language of your internal systems and whispers that data to the physicians who prolong your life.

So how's that for some ink?

I Sing the Tattoo Electric

In the future, epidermal electronics like this may beam infant vital signs right to mom's smartphone.

Todd Coleman/UC San Diego Jacobs School of Engineering

Say what you will about modern medicine, but there's no corner of the human body that we can't prod and probe with technological precision. From brain scans to blood tests, you're just a needle prick, a skull cap and a half a dozen electrodes away from a barrage of test results. But that's exactly what hampers extended monitoring outside the hospital.

After all, a police informant wouldn't carry a bulky audio recorder into a meeting with a deadly mob boss, would he? No, he'd wear as minimally invasive a wire as possible -- something that wouldn't hamper his style or draw unwanted attention. Likewise, no one wants to lug a battery pack and wear clusters of skin-irritating suction cups for daily health monitoring.

That's where the notion of epidermal electronics promises to change the game, allowing continued health monitoring in the real world without unnecessary hindrance.

The University of Illinois at Urbana-Champaign's Dr. John A. Rogers set his sights on the possibilities of electronic tattoos back in 2008, founding his "electronics everywhere" (and he means everywhere) company MC10. With a background in both applied physics and chemical engineering, Rogers aimed to bridge the man/machine gap in health care by making electronics more organic. In other words, he set out to create technology that bends and conforms to the squishy, sticky, leaky, itchy, hairy world of our bodies in motion.

Silicon provided the first major hurdle to this world of skin-soft cybernetics. Believe it or not, this substance originates not in Hollywood breast implants but in a crude, gray crystal mined from the Earth. From this, we create the brittle computer chips that power our high-tech lives.

How do you make this rigid technology bendable and stretchable? Rogers and his team arranged tiny silicon wires into coiling patterns and wove them through slender rubber patches. These coils expand, they contract and link all the functional parts of the device from the sensors and antennae to LED lights.

Need to have an EEG to measure your brain waves? Just slap a patch on your forehead, apply some over-the-counter liquid bandage spray and continue your afternoon on the beach as planned. The patch collects energy from the sun, reads your vitals and then transfers the data out to an external device. Earlier models still depended on a wired connection between patch and computer, but Rogers' team continues to work on improved wireless transmission systems -- including WiFi and network compatibility.

Early electronic tattoos monitored muscle, heart and brain activity. From there, the developers expanded into pregnancy monitoring in humans and actual muscle stimulation in rats. Rogers has also introduced the technology beneath the skin, using stretchable electronics on a balloon catheter inserted inside the human heart.

And if you think all of that sounds high-tech, just wait until you read what Rogers envisions for the future.

But ... Animated Tattoos!

What? Game-changing health monitoring technology isn't good enough for you? Well, fear not, you can still use an illegal, programmable, subcutaneous visible implant to ennsure the monkey tats on your back actually dance the funky mamba. Read more about them in How Animated Tattoos Work.

The Future of Electronic Tattoos

It's not going on your skin. It's going in your heart. Here we see stretchable electronics mounted on the elastic surface of a balloon catheter.

Photo courtesy of the University of Illinois Urbana-Champaign

Electronic tattoos may not be available yet at your local hospital, but Dr. John A. Rogers and his cohorts at MC10 envision a future defined by epidermal electronics.

Far from mere passive observers of human anatomy, Rogers sees electronic tattoos as active agents in rehabilitation. Through the stimulation of muscle contractions, patches may help patients walk again following long periods of immobilization in a hospital bed. The technology may also streamline the use of prosthetic limbs, serving as the vital link between biology and machine.

For instance, one of Rogers' researchers placed an epidermal electronic device on his neck and used muscle movements to control a computer game. He spoke a word and the virtual game world responded. From here, the researchers imagine a world where such patches pick up on the muscular movements of speech to give voice to the mute and allow covert military operatives to speak silently to their home base [source: Gonzalez].

From this point, it's easy to extrapolate not only improved prosthetic limbs and robotic exoskeletons, but also a complete blurring of the line between man and machine. Biological inputs dictate the behavior of machines, and electronic signals inform expressions in the human body. In this, we become a true race of cyborgs -- only not one in which humans are grotesquely broken to meet the rigid demands of technology, but one where technology is forced to conform to the soft and subtle ways of the flesh.

And naturally, it would also mean crazy-awesome video game controllers for everyone. But before we reach that lofty point where the distinction between man and Mario Brother all but fades away, Rogers hopes to "eliminate the need for surgical interventions in the first place" [source: Ornes].

Now, wouldn't you agree that's a little more impressive than a pectoral flag tattoo that glows in the dark?

Author's Note

Senior Staff Writer Robert Lamb

HowStuffWorks 2009

What is our cybernetic future? Well, for starters, we have to consider our cybernetic present. Billions of modern humans are technologically augmented in some way, shape or form. Is there a tiny computer strapped to your wrist or plugged into your ears? Do artificial lenses help you see? We already live in a cybernetic age, and it's not a trend I see us abandoning anytime soon.

The Borg from "Star Trek" represent a nightmarish vision of the cyborg, embodying the fear that our technology will twist us into a grotesque and machinelike existence. And who knows? Maybe it will. Maybe it has already. But the development of epidermal electronic systems represents a bright point in our steady march toward the dawning of the man-machine. Increasingly, we force the technological world to conform to human physiology, human form and human life. The cyborg of the future, then, becomes a creature in which humanity is augmented rather than diminished.

Of course, not every human tendency demands mechanical enrichment -- but that's a different nightmare altogether.